A fundamental principle of displaying a frame of image by a Thin Film Transistor-Liquid Crystal Display (TFT-LCD) is that, a square wave with a certain pulse width is applied to each row of pixels sequentially from top to bottom by a gate driving circuit, so that corresponding pixels are selected and turned on, and then a desired signal is applied to each pixel of the selected row of pixels by a source driving circuit. A gate driving voltage for selecting and turning on each row of pixels is generated by the gate driving circuit, and the voltage of the voltage source of the gate driving circuit is generated by a charge pump circuit, which is used to boost a relatively low input voltage to a relatively high output voltage.
It is known to those skilled in the art that the voltage outputted by the charge pump circuit is positively related to operating frequency of the charge pump circuit. In the prior art, in order to meet requirements for outputting all kinds of images (including heavy-load images and light-load images), the operating frequency of the charge pump circuit in an initial state is generally set to meet the requirement for outputting an image with the heaviest load, which means the operating frequency is rather high. In doing so, although the requirement for outputting an image with the heaviest load is satisfied, it brings about a waste of resources in a case where light-load images make up the majority of all images. Actually, respective rows of pixels can also be driven by the charge pump circuit with a relatively low operating frequency, whereas no specific technical solution exists in the prior art to this end.